This invention relates to anti-theft devices for locking onto a car steering wheel to prevent or limit its movement.
Vehicle anti-theft devices are known in the form of a steering immobiliser bar having means by which it can be locked onto a vehicle steering wheel in a position in which a part of the bar projects from the wheel so that its movement is obstructed by encounter of the bar with a fixed part of the vehicle.
Some of the devices of that form comprise a bar in two telescopically slidable sections which have retaining hooks for engagement with diametrically opposed portions of a steering wheel rim. In order to fit the device, the bar is positioned against the steering wheel and then extended to bring both retaining hooks into engagement with the wheel rim, and the bar sections are then locked together (see e.g. United Kingdom Patent 1127524). The nature of these manipulations deters some drivers from making habitual use of such a device when leaving their cars. Moreover there is a risk of the devices being locked without being properly engaged with the steering wheel.
U.S. Pat. No. 4,134,282 discloses a steering immobiliser comprising an L-shaped member with a fastening device fitted near the junction of the two limbs of the L. The immobiliser is designed for fastening onto a steering wheel rim at the top of the wheel so that one limb of the L-shaped member extends downwardly across the wheel while the other limb extends over the wheel and overlaps the top edge of the dashboard or instrument panel. An immobiliser of this design has merely to be bodily placed in correct position on the steering wheel before being fastened. However this advantage is achieved at the cost of less versatility. The form and dimensions which the immobiliser must have in order that it can be fitted in the intended manner would make it unsuited to more than a limited range of motor car models. Moreover, in order that the immobiliser can be fitted to flat as well as to dished steering wheels, provision has to be made for moving the fastening device from one position to another on the L-shaped member. A further disadvantage is that when the immobiliser is fitted to a flat steering wheel a limb of the L-shaped member can be used as a long lever arm to subject the immobiliser to very strong forces which may deform or break it.